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Báo cáo khóa học: Mutations in the hydrophobic core and in the protein–RNA interface affect the packing and stability of icosahedral viruses

The information required for successful assembly of an icosahedral virus is encoded in the native conformation of the capsidproteinand in its interactionwith the nucleic acid. Here we investigated how the packing and stability of virus capsids are sensitive to single amino acid substitutions in the coat protein. Tryptophan fluorescence, bis-8-anilinonaph-thalene-1-sulfonate fluorescence, CD and light scattering were employed to measure urea- and pressure-induced effects on MS2 bacteriophage and temperature sensitive mutants. . | Eur. J. Biochem. 271 135-145 2004 FEBS 2003 doi 10.1046 j.1432-1033.2003.03911.x Mutations in the hydrophobic core and in the protein-RNA interface affect the packing and stability of icosahedral viruses Sheila M. B. Lima1 David S. Peabody2 Jerson L. Silva1 and Andrea C. de Oliveira1 1Departamento de Bioquimica Médica Instituto de Ciencias Biomedicas and Centro National de Ressonância Magnética Nuclear de Macromoléculas Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil -Department of Molecular Genetics and Microbiology and Cancer Research and Treatment Center University of New Mexico School of Medicine Albuquerque NM USA The information required for successful assembly of an icosahedral virus is encoded in the native conformation of the capsid protein and in its interaction with the nucleic acid. Here we investigated how the packing and stability of virus capsids are sensitive to single amino acid substitutions in the coat protein. Tryptophan fluorescence bis-8-anilinonaph-thalene-1-sulfonate fluorescence CD and light scattering were employed to measure urea- and pressure-induced effects on MS2 bacteriophage and temperature sensitive mutants. M88V and T45S particles were less stable than the wild-type forms and completely dissociated at 3.0 kbar of pressure. M88V and T45S mutants also had lower stability in the presence of urea. We propose that the lower stability of M88V particles is selaled to on increase in the eachy yf the hydrophobic core. Bis-8-anilinonaphthalene-1-sulfonate fluorescence increased for the pressure-dissociated mutants but not for the urea-denatured samples indicating that the final products were different. To verify reassembly of the particles gel filtration chromatography and infectivity assays were performed. The phage titer was reduced dramatically when particles were treated with a high concentration of urea. In contrast the phage titer recovered after high-pressure treatment. Thus after pressure-induced dissociation of the .